Japanese Patent Laid-Open No. 194886/1994 discloses an image formation apparatus which irradiates a charged photosensitive drum with light to change the potential of the irradiated portion to thereby form an electrostatic latent image on the photosensitive drum, supplies toner to the electrostatic latent image to form a toner image, and then transfers the toner image to a record sheet to thereby form a predetermined image on the record sheet.
The image formation apparatus includes a plurality of photosensitive members, developer cartridges storing toners of different colors, and a plurality of developing devices for supplying the toners in the developer cartridges to the photosensitive members. Each of the developing devices has an opening for receiving the toner from the corresponding developer cartridge and a shutter for opening and closing the opening.
If the shutters of the developing devices as described above are opened and closed separately, there is a problem of poor operability.